Windows power management is turning off the USB root hub. Go to Device Manager → Universal Serial Bus controllers → USB Root Hub → Properties → Power Management → Uncheck "Allow the computer to turn off this device."

Before troubleshooting, it is essential to understand the underlying technology.

: Temporarily disable antivirus software during installation, as it may block driver files or activation tools. Firmware Mismatch

: If the driver is installed but the software still can't "see" the VCI, you might need a Firmware Update . This must be done with the device connected to both the car (for power) and the PC (for data) via USB.

Yes, but the driver must be 64-bit compatible. The Prolific v3.2.0.0 driver has both 32 and 64-bit versions. Avoid unsigned 32-bit only drivers.

Remember: The golden rules are:

The driver acts as a bridge, converting the USB signal from your computer into a serial communication format that the diagnostic tool understands. It typically appears in your computer's under two sections: Universal Serial Bus controllers (as Autocom CDP+ USB) Ports (COM & LPT) (as VCI Diagnostic Unit Serial Port) How to Install the Autocom CDP USB Serial Port Driver

Windows does not always release COM port numbers. If you have plugged the CDP into several different USB ports, Windows creates multiple ghost COM ports, leading to "Access is denied" or "Port already in use" errors.

Red LED typically means power but no communication. Double-check your Autocom software version. Some software (e.g., Delphi 2015) requires a specific firmware version on the CDP itself.

After this, install Prolific driver v3.4.62.298 (the last version before aggressive blacklisting). This trick works on Windows 7, 8, and 10 (but rarely on Windows 11).